System of burning solid fuel



Jan, 13, l 925.

R. E. SCHURTZ SYSTEM OF BURNING SOLID FUEL Filed NOV. 29, 1920 2 Sheets-Sheet A 1 ffy/W 1 bo/L Sc/LLL @fk/MAW Jan, 13. l 925.

' R. E. SCHURTZ SYSTEM oF BURNING SOL-ID FUEL Filed Nov. 29, 1920 2 Sheets-Sheet 2 |i| /A |i| Ill 7'] lll/[Jl] l1 Ill/ll Illllllllllllll Il llll M- www Patented `lan. 13, 1925.

UNITED STATES RALPH n scr-mara, or KANSAS cr'rY, mrssonm.

.sYs'rEm or BURNING soLrn rum..

Application filed November 29, 1920. Serial No. 427,179.

To all whom it may concern:

Be it known that l, RALPH E. SoHUR'rz, citizen of the United States, and resident of Kansas City, county of Jackson, State of Missouri, have invented a certain new and useful Improvement in Systems of Burning Solid Fuel, of which the following is a complete specification.

This invention relates to a method of and apparatus for burning solid fuel, and has for its prime object to provide for the etlicient and accurate regulation of combustion through automatic replenishment of fuel to and elimination of ashes from the grate or point of combustion. A further object is to provide apparatus of the character suggested in which the position of the rear end of the mass of burning fuel, or fire line, is utilized as the agency for controlling the feed of the fuel and elimination of ashes, and hence the maintenance of a uniform fire condition without personal attention except for occasional charging of the feed hopper or magazine of the apparatus. An apparatus for e'cctively accomplishing the objects set forth, is desirable not only because it would require but little personal attention but also because its operation would result in the greatest possible conservation of fuel in proportion to the heat generated, in that there would be no periods of radical variation of combustion as is inpredetermined point or line as possible, the` recession of such fire line through substantial consumption of the fuel thereat, resulting in a cooling and consequent collapse of a thermostat and in the displacement of liquid to a postion convenient for vaporization forward of the predetermined point y of the re line; the steam thus generated causing reexpansion of the thermostat and such grate travel as shall replenish the fuel on the grate at the front end thereof, and effect discharge of ashes accumulated rearward of the said fire line. The travel of the grate moves the re line rearward, and as the tire line approximately reaches the predetermined point, it vaporizes liquid to maintain the thermostat in inoperative or expanded condition until the next recession of the fire line occurs, when the action traced is repeated. lit will be understood of course, that there may be times when more than one travel action of the grate is necessary to restore the fire line to the theoretically predetermined point. For example, the consumption of fuel may be relatively so rapid at the rear end of the grate that the fire line recedes a greater distance than the normal grate travel, in which event the fire line could not be brought back to the predetermined point until the grate had been moved two or, in some cases, perhaps, more times, by a corresponding number of eXpansions of the thermostat, it being obvious that play or lost motion in the actuating mechanism might be a factor affecting the length of travel of the grate.

A further object is to provide eflicient means of the character set forth, which is susceptible of application to stoves, hot air, hot water and steam furnaces, power boilers and industrial heating plants and the like.

With these objects in view the invention consists in certain novel and useful features of construction and combinations of parts as hereinafter described and claimed; and in order that it may be fully understood reference is to be had to the accompanying drawings, in which:

Figure l, is a central vertical section of a furnace equipped with apparatus embodying the invention.

Figure 2, is an elevational view of the apparatus with certain parts thereof shown in vertical section.

Figure 3, is a horizontal section on an enlarged scale, taken on the line Hl--IH of Figure l.

Figure 4, is a vertical section of part of the apparatus taken on the line lV-IV of Figure 5.

Figure 5, is a horizontal section taken on the line V-V of Figure 4.

Figure 6, is a vertical sect on taken on the dotted line VI-VI of Figure 4.

Figure 7, is a fragmentary perspective view of a slightly modified form of steam generating tube.

Before describing the construction and operation of the apparatus in detail, it is desired to state that the term re line as used in connection with a traveling grate means the rear or advanced end of the mass of live or incandescent fuel on the grate, and it will be understood that this fire line,

through substantially complete combustion during the periods when the grate is stationary, tends to recede or move toward the front end of the grate and leave an accumulation of ashes back of it, which ashes, on the following rearward movement` or movements of the grate, are dumped thereby, it being also understood that on each movement of the grate, the fire line or rear end of the mass of burning fuel is brought toward the original point, and additional fuel is taken up by the front end of the grate. It wll be also understood that if these operations are infallA ble, and the advance movement of the grate effected quickly and before appreciable recession of the fire line can occur, such line can be maintained at a substantially fixed point within the furnace, and that the heat produced will be substantially un`form provided there is proper regulation of the draft.

To accomplish the objective set forth, a thermostat and mechanism related thereto are employed, the preferred type of thermostat comprising a bellows member set away from the direct influence of heat; a liquid vaporizing tiibe member connected at one end to the lower part of the bellows member and having its other end alongside and in proximity to the grate and preferably sloping downward with respect to the bottom of the bellows member; a plun er for preventing liquid, at times, from owing from the vaporizing member into the bellows member and, at other times, for forcing liquid from the latter into said vapor'zf ing member; means actuated by the expanding bellows for raising the plunger to permit liquid to flow from the vaporizing melnber toward or into the bellows member; means actuated by the expanding bellows, to advance the grate; and means adapted when ,the steam condenses, to relower the plunger and force the l'quid back into the vaporizingmember for revaporization: these actions occurring automatically and in such order, that the fire line is maintained at a depth or point within the furnace, which var'es so slightly as to be hardly noticeable to the eye. It will therefore be understood that the bellows is normally expanded, and that while it is collapsed at fairly regular periods, it almost instantly reexpands, and remains in such condition until the steam wh'ch expands it, is condensed and produces a vacuous condition within and consequent collapse of the bellows, the plunger moving downward to displace the condensation or water for the purpose of positioning it again for revaporization.A

Referring now to the drawings in detail, where like features are identified by corresponding reference characters, l indicates a fuel magazine for supplying solid fuel to a grate 2, which in this instance appears as of the endless travelling or stoker type, in which the customary wheels 3 3 are mounted upon shafts 4 4 journaled in a frame 5 which is fastened to the side walls of the furnace in any suitable manner. The grate 2 is operated by a sprocket wheel 6 mounted on shaft 4 rotated at irregular intervals by a metal bellows or thermostat 7 through a link 8 connected to an-arm 9, pivoted to said shaft. A pawl consists of awei hted arm 9 pivoted to arm 9, and a pivote tooth 9', adapted in the upward movement of the bellows, to turn the ratchet wheel 10 and operate the grate for the replenishment of fuel and the discharge of ashes, said tooth upon reverse movement of the bellows, being adapted to slip over the ratchet wheel preliminary to obtaining a new grip upon the same forthe purpose of again operatlng the grate bellows u on the next expansive or upward action of the bellows.

In the event the grate becomes clogged, due to such reason as interference offered by an accumulation of ashes, the weighted end of the pawl or catch will swing upward when the thermostat expands and thus avoid chance of injury to any of the working parts.

11 indicates the ash pit under the grate 2, and 12 an ash pit trap which, at its lower end, retains sufficient ashes to prevent air from flowing up around the rear end of the grate 2 and thus compels all of the air to pass up through the grate itself. lindicates a heating drum and 14 is a lire brick or other refractory crown, over the grate, carried by a gate or door 15 mounted on the` magazine. The gate or door 15 with the crown kf, is slidable up or dgwn so as to regulate the depth to whch fuel may accumulate on the ,grate by flow or feed through the gate opening. The parts 13 to l5 may be of any suitable or conventional type as `they form no essential part of the invention.

in fact this statement applies to the furnace as a whole, as any type of furnacev or heat generating appliance or apparatus may be employed in which provision is made for an automatic feed or replen'shment of fuel to and discharge of ashes from the grate, and in this connection it may be noted that conventional or other types of thermostatic draft control may beemployed in this system of combustion.

Referring now to the mechanism for actuating the grate, it will be noted that the bellows 7 ,-the preferred type of expansive tained.

thermostat member employed,--is enclosed for protective reasons within a housing 16 and is preferably located exterior tothe combustion chamber, as shown clearly by inafter appears. Thiscasing forms the bottom part of the chamber of the bellows. A vapor-generating tube is shown as consisting of a tl-shaped member 21 which communicates at one end with the lower part of the casing 20 and extends in a horizontal direction through the adjacent wall of the combustion chamber, and a vaporizing part or member` 22 within the said chamber and between said wall and the adjacent edge of the grate as shown, or above, or at any equivalent point therein, said member 22 sloping slightly upward from its point of connection with member 21 to its opposite end which is closed. ln this connection it will be noted that where the member 22 joins the llshaped member 21, the bottom o-f the former stands in a slightly higher plane than the bottom of the latter, this point being indicated inFigure 1 at P at or near which point the fire line or advanced end of the live fuel on the grate is desirably mainln this connection it should be stated that the part 22 of the vaporizing tube is intended to serve for instant or Hash generation whenever it is charged with liquid..to effect expansion of the bellows,

and that part 21 serves as a generator to.

maintain the bellows expanded only when the fire line is a roximatel at the oint y PP Y P P, as at such time the live fuel is close enough to vaporize liquid collected in the part 21 in such small quantity that none at that time. can flow back into member 22. Because of this, the parts 21 and 22 actually' perform distinct functions-one to sustain and the other to effect thermostatic expansion of the bellows, as above explained, and hence could be separately formed, provided each was connected at one end tothe bellows casing and was closed at the other end.. To facilitate generation of vapor the chamber of the tube is preferably narrow horizontally measured and wide when measured vertically. It may be found desirable in some situations to laterally widen the tube at the upper edge as indicated at 21a in the modified form of construction shown by Figure 7, this wideningl of the chamber of the tube providing for increased vapor capacity.

Flange plate 18 carries a bearing 23 and at a diametri'calljv opposite point, a slotted bearing 24, respectively constituting journals for parallel shafts 25 and 26. 27 indicates an arm projecting inwardly from shaft 25, and 28 a similar arm projectlng inwardly from shaft 26, arm 27 having a notched or forked free end and the arm 28 a pointed end engaging thejsaid notched end of arm 27. The shafts mentioned terminate in projecting ends connected together by retractile springs 29, the pull of said springs holding the arms 27 and 28 in interloched relation and either depressed or elevated at their free ends, the slotted bearing 24 permitting said arms to rock, as. hereinafter explained.

Secured to and depending from the head 17 o-f the bellows member of the thermostat, is a bar 30 provided with upper and lower lugs 31 and 32, and said head is` also equipped with a pair of depending bars or rods 33 equipped with upper and lower lugs 34 and 35. The lugs 31 and 32 stand respectively in planes above and below the arm 27 for alternate engagement thereby, and the lugs 34 and 35 likewise stand in planes above and below the ange plate 18 for alternate engagement therewith, it being noted by reference to Figure 4, that the inner margin of the flange-plate 18 is inward of the corresponding margin of plate 19, and by reference to Figure 5, that the inwardly-projecting margin of plate 18 is overlapped and under-lapped respectively by said lugs 34 and 35. The lugs 34 and 35 respectively limit the contraction and expansion of the bellows 7. The function of the lugs 31 and 32 will hereinafter appear.

rllhe plate 18-is equipped with a bridgebearing 36 carrying a pivoted catch 37 equipped with a weight 38, and with an arm 39, and extending through the arm 27 adjacent the bar 30, which also extends through said arm as shown clearly by Figure 5, is a vertical stem 40 projecting upward from a liquid displacing plunger 43 within the cylindrical casing 20, and said stem is provided above the arm 27 with an overlapping lug 41. and adjacent the said plunger with a notch 42. When the bellows stands in collapsed condition, the arm 28 by engagement with arm 39 holds the catch 37 out of engagement with the stem 40 of the plunger, and when the bellows expands, the catch engages the notch 42 and locks the plunger in the elevated position to which it is raised by pressure applied on lug 41 of stem 40, by the arm 27. It will be noticed by reference to Figures 2 and 4, that when the bellows is collapsed, the liquid displacing plunger 43 stands on the bottom of the casing 20 and hence holds the charge of liquid entirely within the members 21 and 22 of the generating tube. In practice the quantity or charge of liquid is small, preferably so small that when it stands in member 21 and in the casing,-at which time the plunger 43 is raised,-no liquid is standing in the inclined member 22, and in order4 to gauge the supply of liquid readily, the

casing is preferably provided with a plug 28 controlling an opening in the plane ot' the bottom of member 22 where it joins with the member 21, as indicated in Figure 2. By this arrangement the removal of the plug 28 will permit any excess quantity of liquid to drain from the tube through the plug-controlled opening after which. said plug is secured in position.

'l`o insure positive collapse of the thermostat when condensation of vapor occurs therein, 'it is desirable to provide a partial vacuum in the thermostat bellows before its practical use is begun. To accomplislr this purpose the liquid inthe tube is heated in any suitable manner to generate vapor and then the valve in the bent tube 7a of the bellows is opened to permit this steam to expel any air contained Within the theru'iostat, the valve being immediately closed when it is noted that the vapor begins to escape. The vent tube forms a convenient means for supplying the charge of liquid.

Should it be necessary to dispose the thermostat bellows in a position where it would be exposed to drafts of comparatively cool or cold air, the housing 16 will be found desirable asv a protection. The housing, which is open at the bottom, is provided with a ventilation opening 16a normally closed by a thermostatic bar 16", said bar being adapted to uncover the opening 16a in the event the interior of the casing attains a predetermined temperature, so that air may circulate through and lower the temperature of the thermostat and thus insure rapid condensation of steam within it.

Assuming that the magazine contains fuel susceptible of automatic movement down upon the grate 2 when. the gate 15 is open, it will be apparent that when comlnlstion has progressed sufliciently upon the grate, the proximity of thel live fuel at the side of the grate to part 22 of the vaporizing tube, will'result in the generation of vaporif at the time, liquid is within such tube, and vapor or steam will pass from the upper part 'of said tube through the corresponding part of the member 21 and enter the casing above the plunger, this action resulting in effecting the expansion of the bellows through the internal steam pressure therein. As the bellows starts to expand, the lug 32 on the lower end of bar 30, applies upward pressure on the arm 27, and overcoming the resistance of springs 29, causes the arms 27 and 28, because of their interlocking relation, to swing upwardly beyond the plane of their respective axes, and as this occurs the retractive action of said springs continues the upward h movement of said arms until they are arrested by Contact of arm 27 with lug 31, and immediately thereafter the lugs 35 abut against the underside of flange plate 18 and check expansion of the bellows. The expansion of the bellows and the upward swinging movement of arm 27, results in the latter applying upward pressure on lug 41 of stem 40 and raising the plunger, this condition being maintained by the action of the gravity catch 37 which is yicldingly impelled by the weight 38 t0 enter notch Ll2 on bar 40.A Immediately the plunger is elevated as explained any liquid standing in tube arm 22 flows down into the lower end of the bellows casing 2O and also stands in small quantity in the tube member 2l. If the tire line has advanced to or beyond point P, the liquid in member 21 is vaporized and the vapor applies pressure to hold the bellows expanded until combustion has continued suficiently to cause the fire line to recede from point l. As a result the vapor is condensed in member 21 and the bellows and thus creates a partial vacuum in the latter which results in its collapse, which obviously will happen quickly because 0f the relative coolness of the thermostat due to its location. As the top of the bellows moves downward, lug 31, of rod 30 moves arms 27 and 28 downward until the knife.

edge joint of said arms passes slightly below the plane of the axis thereof. As this occurs springs 29 cause the arms to snap downward until arm 27 is arrested by the lug 32, and arm 28 strikes the arm 39 and forces the catch 37 out of notch 42 and permits the plunger to gravitate to the bottom of chamber 20, and thus effect the displacement of the liquid therein, the liquid backing upward within the inclined member 22 of the generation tube, where it is quickly reconverte'd into steam which again expands the bellows.

It will be noted that when the bellows expands the pawl or catch imparts movement to the grate and that when the bellows collapses, the pawl or catch is reset to again actuate the grate upon the next expansive action of the bellows.

As hereinbefore stated, the thermostatic bar can be used with the stoker type of grate to guard against premature collapse of the bellows, but in such event, it is desirable to dispose a heat-insulating arch transversely over the grate at about the line P, to protect the bar,-preferably arranged beyond said line-from radiant heat, so that said bar shall not operate until the tire line on the grate passes said arch and shall 4not react until the fire line has dropped back to the said arch. It will be noted that in the construction shown the ashes on the gratcwill act as such an insulator of tube 21.

In stokcr construction employing drives from line shaft, engine or electric motors, the methods herein shown for maintaining a fire line 'or condition can be employed for controlling the feed to maintain the desired fire condition.

From the above description it Will be evident that I have produced a system of burning solid fuel, which possesses all the features pointed out as desirable in the statement of the object of the invention, and it is to be understood that I reserve the right to make all changes properly falling wvithin the spirit and scope of the appended claims.

lt claim:

l. The combination of a furnace having an operable grate in which the consumption of the fuel thereon, results in a recession of the position of the fire line thereof, means for operating the grate, and thermostatic means operable through deviation of the position of the fire line on the grate for controlling the operation of the grate-operating means.

2. The combination of a furnace having a traveling grate in which the consumption of fuel on the rear end of the grate results in a recession of the position of the fire line of the fuel, means for operating the grate, andv thermostatic means operable through deviation of thevposition of the fire line on the. grate for controlling the operation of the first-named means.

3. The combination of a furnace having an intermittently movable grate, the consumption of fuel at the rear end of the grate resulting in recession of the fire line thereof, and the movements of the grate discharging ashes produced by such consumption of fuel and shifting the fire line toward the point it occupied While the consumption of such fuel Was in progress, and a thermostat having a part always in proximity to the burning fuel, and a part in proximity to the fire line of such fuel only after the said movements of the grate; the first-named part being influenced by the heat to expand the thermostat but not hold it expanded, and the other part to hold the thermostat inoperative until sufficient recession of the fire line occurs through consumption of fuel at the rear end of the grate.

4. The combination of a furnace having an intermittently movable grate, the consumption of fuel at the rear end of the grate resulting in recession of the fire line thereof and the movements of the grate discharging ashes produced by Such consumption of fuel and shifting the fire line toward the point it occupied While the consumption of such fuel was in progress, and a thermostat having a part also in proximity to the burninfr fuel, and a part in proximity to the lire line of such fuel only after the said movements of the grate; the first-named part being inuenced by the heat to ex and the thermostat but not hold it expande and the other part to hold the thermostat inoperative until sufficient recession of the re line occurs, and

means actuated by collapse of the thermostat, to bring the first-named part again under the influence of the heat to eect the reexpansion of the thermostat.

5. The combination in a furnace, of a grate for the burning -of solid fuel, a thermostat having means actuated by heat from fuel burning on the grate for expanding the thermostat and uninfiuenced by the heat during the period of such expansion, and means actuated by the operation of the thermostat, for imparting movement to the grate; the thermostat also having means actuated by a change in the position of the fire line on the grate, for holding the thermostat inoperative.

6. rThe combination in a furnace, of a grate for the burning of solid fuel, la thermostat having means actuated by heat from fuel burning on the `grate for vexpanding the thermostat and uninfluenced by the heat during the period of such expansion, means actuated by the operation of the thermostat, for imparting movement to the grate; the thermostat also having means actuated by a change in the position of the lire line on the grate, for holding the thermostat inoperative, and means for replenishing the fifiel on the grate after each movement thereo 7. The combination in a furnace, of a grate for the burning of solid fuel, a thermostat having means actuated by heat from fuel burning on the grate for expanding the thermostat and uninfluenced by the heat during the period of such expansion, means actuated by the operation of the thermostat, for imparting movement. to the grate; the thermostat also having means actuated b v a change in the position of the fire line on the grate, for holding the thermostat inoperative, and means actuated by the movement of the grate for effecting replenishment of the fuel thereon.

8. 'Ihe combination of a furnace having a grate for intermittent travel, a thermostat having a liquid-holding portion always in proximity to live fuel on the grate for the generation of vapor. at times, to expand the thermostat, and means for transmitting power from the thermostat as expanded, to the grate` to effect travel thereof; the thermostat also having a portion exposed to the influence of the fire line on the grate only when the approximately full travel of the grate is effected, to maintain the thermostat in inoperative condition until generation of vapor, at times, to expand the thermostat, means for transmitting power from the thermostat as expanded, to the grate, to effect travel thereof; the thermostat also having a ortion exposed to the influence of the lire ine on the grate only when the approximately full travel of the grate is effected, to maintain the thermostat in inoperative condition until consumption of fuel provides ashes onr the grate back of the said fire line, for insulating the lastnamed portion of the thermostat from vaporizing proximity to the tire line, and means for forcing Huid produced by condensation of vapor within the thermostat, back into the liquid-holding portion of the thermostat for revaporization by the heat from the burning fuel.

. 10. The combination in a furnace, of a grate for the burning of solid fuel, and a thermostat comprising a bellows portion disposed beyond the influence of radiant heat from the furnace, a liquid-holdingr portion arranged in proximity to fuel on the grate and closed at one end and communicating with the bellows, and a lliquid-holding portion communicating with the bellows and the first-named portion, and susceptible to the vaporizing influence of heat from the fuel on the grate only when the fire line thereof has attained approximately a predetermined position, and adapted at such time to vaporize condensed liquid for the purpose of holding the bellows inoperative.,

11. The combination in a furnace, of a vgrate for the burning of solid fuel, a thermostat comprising a bellows portion disposed beyond the influence 'of radiant heat from 'the furnace, a liquid-holding portion arranged in proximity to fuel on the ate and closed at one end and communicatmg with the bellows, and a liquid-holding portion communicating with the bellows and the first-named portion, and susceptible to the vaporizing infiuence of heat from the fuel on the grate only when the fire `line thereof has attained approximately a predetermined position, and adapted at such time to vaporize condensed liquid for the purpose of holding the bellows inoperative, and means adapted upon-the collapse of the bellows from condensation of the vapor therein following recession of the fire line through consumption of fuel on the grate, to force the condensed vapor from the bellows back into the said vaporizing portions thereof.

12. The combination in a furnace, of a grate for the burning of solid fuel, a thermostat comprising a bellows portion disposed beyond the inliuence of radiant heat from the furnace, a liquid-holding portion arranged in proximity to fuel on the grate and closed at one end and communicating d with the bellows, and a liquid-holding portion communicating with the bellows and the first-named portion, and susceptible to the vaporizing influence of heat from the fuel on the grate only when the fire line thereof has attained approximately a predetermined position, and adapted at such time to vaporize condensed liquid for the purpose of holding the bellows inoperative, means adapted upon the collapse of the bellows from c'ondensation of the vapor therein following recession of the fire line through consumption of fuel on the grate, to force the condensed vapor from the bellows back into the said vaporizing portions thereof, and means for withdrawing said liquid forcing means to inoperative position upon each expansive operation of the bellows.

13. The combination in a furnace, of a gratelfor the burning of solid fuel, a thermostat comprising a bellows portion disposed beyond the influence of radiant heat from the furnace, a liquid-holding portion arranged in proximlty to fuel on the'grate and closed at one end and communicating with the bellows, and a liquid-holding portion communicating with the bellows and thc first named portion, and susceptible tothc vaporizing influence of heat from the fuel on the grate only when the fire line thereof has attained approximately a predetermined position, and adapted at such time to vaporize condensed liquid for the purpose of holding the bellows'inoperative, means adapted upon the collapse of the bellows from condensation of the vapor therein following recession ot' the fire line through consumption of fuel on the grate, to force the condensed vapor from lthe bellows' back into the said vaporizing portions thereof, and means actuated by the expanding bellows for withdrawing the liquid forcing means to' inoperative position.

14. The combination in a furnace, of a grate for the burning of solid fuel, a ther`v mostat.` comprising a bellows portion disposed beyond the influence of radiant'heat from the furnace, a. liquid-holding portion arranged in proximity to fuel on the grate and closed at one end and communicating with the bellows, and a' liquid-holding portion communicating with the bellows and the first-named portion, and susceptible t the vaporizing infiuence of heat from the fuel on` the grate only when the' tire line thereof has attained approximately a predetermined position, and adapted at such time to vaporize condensed liquid for the purpose of holding the bellows inoperative. means adapted upon the collapse of the bellows from condensation of the vapor therein following recession of the lire line through consumption of fuel on the grate, to force the condensed vapor from the bellows back into the said vaporizing portions thereof, means for withrawing said liquid forcing means to inoperatlve position upon each expansive operation of the bellows, and an automatic latch for securing the said forcing means in inoperative position.

15. The combinationl in a furnace, of a grate for the burning of solid fuel, a thermostat comprising a bellows portion disposed beyond the' influence of radiant heat from the furnace, a liquid-holding portion arranged in proximity to fuel on the grate and closed at one end and communicating with the bellows, and a liquid-holding p0rtion communicating with-the bellows and the first-named portion, and susceptible to the vaporizing influence of heat from the fuel on the grate only when the fire line thereof has such time to vaporize condensed liquid for the purpose of holding the bellows inoperative, means adapted upon the collapse of the bellows from condensation f the vapor therein following recession of the 'lire line through consumption of fuel on the grate, to force the condensed vapor from the bellows back into the said vaporizing portions thereof, means for withdrawing said liquid forcing means to inoperative position upon each expansive operation of the bellows, an automatic latch for securing the said forcing means in inoperative position, and means for tripping the latch upon the collapse of the bellows, to cause said forcing means to expel condensed vapor from the bellows.

16. The combination of a grate for the burning of solid fuel, a thermostat comprising a bellows, a liquid-holder adjacent the ate and closed at one end and commumcating with the bellows, liquid-displacing means for holding the liquid in the holder and within the heating iniuence of combustion on the grate t0 convert such liquid into vapor to effect expansion of the bellows, means operable initially by the expanding bellows, yielding means for completing themovement of the said initiallyoperable means to cause it to withdraw the displacing means from the path of the liquid, and means actuated by the expansion of the bellows, for moving the grate to effect replenishment of fuel to the grate and discharge of ashes therefrom. y

17. The combination of a grate for the burning of solid fuel, a thermostat comprising a bellows, and a liquid-holding portion adjacent the fuel on the grate, a liquid-displacing means for holding part of the liquid within the heating influence of combustion on the grate to convert such liquid into vapor to effect expansion of the bellows,

means operable initially by expanding the bellows, and yielding means for completing the movement of said initially-operable means to cause it to withdraw said displacing means from the path of the liquid; the thermostat also including means actuated by the fire line of fuel on the grate, when it attains an approximately predetermined position, to vaporize liquid for holding the bellows inoperative. A

18. rllhe combination of a grate for the burning of solid fuel, a thermostat having a bellows member and an inclined vaporizing tube within the heating influence of combustion on the grate, closed at its higher end and communicating at its other end with the bellows, means for preventing liquid within the tube, from flowing into the bellows without interfering with the flow of vapor to expand the bellows, means actuated by expanding movement of the bellows to withdraw the liquid-flow preventing means from the path of the liquid, and means actuated by the expansion of the bellows, fo-r moving the grate. for replenishment of fuel and discharge of ashes.

19. The combination of a grate for the burning of solid fuel, a thermostat having a bellows member and an inclined vaporizing tube within the heating influence of combustion on the grate, closed at its higher end and communicating at its other end with the bellows, means for preventing liquid within the tube from flowing into the bellows without interferingl with the flow of vapor to expand the bellows, means actuated by expanding movement to the bellows to withdraw the liquid-flow preventing means from the path of the liquid, means actuated by the expanding bellows to impart travel to the grate, means actuated by rearward shifting of the fire line by the travel of the grate, for holding the thermostat inoperative, and means actuated by the expanding bellows for withdrawing the liquid forcing means tb inoperative position.

20. In a device for burning solid fuel, having a grate, means for actuating the grate to discharge ashes and effect the replenishment of fuel, thermostatic means to control actuation of'the ate to maintain a -substantially fixed lire line, a housing enclosing the thermostat, having an opening, a thermostatic means normally closing said opening and adapted to uncover it at appredetermined temperature, and means actuated by the heat-influencing action of the thermostat to impart fuel-replenishing and ash-discharging movement to the grate.

ln witness whereof I hereunto aix my signature.

RALPH E. SCHURTZ. 

